Environment

tmux exposes two environment APIs. Process variables such as TMUX and TMUX_PANE let code inside a pane identify its server and pane. The server also stores variables through $set-environment and $show-environment for new processes to inherit. Like the tables in Options and hooks, this persistent store has explicit scopes.

Locating yourself from inside a pane¶

Inside a pane, TMUX contains <socket path>,<server pid>,<session id>, and TMUX_PANE contains the pane ID, such as %1. Use these variables to locate the current tmux objects. Select the object your operation needs:

Server: mServer::from_env()

Session: Not listed.

Window: Not listed.

Pane: Not listed.

Examples¶

Environment lookup requires valid tmux targeting variables. If your process can run outside tmux, handle that case before using the result.

Resolve the server socket¶

mServer::from_env() selects the socket. Use the resulting server to resolve sessions or panes.

tmux’s own environment variable store¶

Like Options and hooks, tmux’s persistent environment store has global and per-session scopes. It is read with $show-environment and updated with $set-environment. Newly spawned processes inherit it; existing processes retain their own environments.

Set: Not documented here; see the process-environment note below.

Read all: Not documented here; see the process-environment note below.

Unset: Not documented here; see the process-environment note below.

set-environment writes a value. Its -u flag removes the entry, while -r marks the variable for exclusion from new processes, including values tmux inherited at startup. The listing retains an excluded variable as -NAME.

Process environment¶

Creation-time environment values affect the new process. They do not update an existing process’s environment. To change tmux’s persistent table, use $set-environment on the same socket as the server handle.